FEC (Forward Error Correction) decoder with dynamic parameters

ABSTRACT

FEC (Forward Error Correction) decoder with dynamic parameters. A novel means by which FEC parameters may be encoded into, and subsequently extracted from, a signal stream to allow for adaptive changing of any 1 or more operational parameters that govern communications across a communication channel. FEC parameters are encoded directly into a data frame such that the data frame is treated identical to all other data frames within the signal stream. When the data frame actually includes FEC parameters, it is characterized as a CP (Control Packet) type. For example, when decoding an MPEG stream, an MPEG block that includes FEC parameters, that MPEG block is characterized as a CP MPEG block. The means by which FEC parameters are encoded and extracted from the signal stream allows for much easier adaptive modification of the manner by which signal are encoded, modulated, and processed within a communication system.

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. § 119(e) to the following U.S. Provisional Patent Applicationwhich is hereby incorporated herein by reference in its entirety andmade part of the present U.S. Utility patent application for allpurposes:

1. U.S. Provisional Application Ser. No. 60/516,826, entitled “FEC(Forward Error Correction) decoder with dynamic parameters,” filedMonday, Nov. 3, 2003 (Nov. 3, 2003 ), pending.

The following U.S. Utility patent application is hereby incorporatedherein by reference in its entirety and is made part of the present U.S.Utility patent application for all purposes:

1. U.S. Utility patent application Ser. No. 10/319,929, entitled“DOWNSTREAM TIME DOMAIN BASED ADAPTIVE MODULATION FOR DOCSIS BASEDAPPLICATIONS,” filed Dec. 12, 2002, pending.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The invention relates generally to communication systems; and, moreparticularly, it relates to decoding processing within suchcommunication systems.

2. Description of Related Art

Various communication systems have been under constant development formany years. Within certain types of communication systems, FEC (ForwardError Correction) is employed such that various parameters employedwithin the receiver end/decoder end of a communication channel areappropriately suited to be able to correct for most (ideally, any)errors that may be introduced within signal transmitted across thecommunication channel from a transmitter end to a receiver end.Sometimes, it is desirable to adjust certain of the various operationalparameters within a receiver end communication device in an effort tocompensate for any changes to the operating conditions (or communicationdevice status) thereby providing relatively good performance and errorcorrection.

However, in order to change these operational parameters within an FECfunctional block within a receiver end communication device, theparameter configuration should be changed on the fly (i.e., in realtime) for adaptive modulation and coding. In order to support thisapproach to performing FEC decoding, the FEC decoding parameters must beknown and programmed to an FEC decoding functional block before inputsignals get into the FEC block. However, the approaches for doing thiswithin the prior art do not provide for very operation and performance.

One prior art way of adaptively modifying the operational parameters foran FEC block is to send the FEC parameter information in frame headersand to extract the FEC parameters out of them. Once these FEC decodingparameters have been extracted from the frame headers, then those FECdecoding parameters may then be programmed back to the corresponding FECblock. This approach is typically a 1 to 1 approach, in that, a headerincludes FEC operational parameter information corresponding to animmediately following and subsequent FEC block. This prior art is shownpictorially in the following described prior art figures.

FIG. 1A is a diagram illustrating an embodiment of a prior art framestructure. In this illustration, it can be seen that the frame headerimmediately preceding an FEC block includes the FEC operationalparameters that correspond to the immediately following FEC block. Thisinformation immediately extracted from the header is then employed toconfigure the FEC decoding parameters that are used to perform the FECdecoding of the FEC block immediately following the frame header. Thisprior art inherently involves an undesirable decoding and operationallatency, in that, the header of the FEC block must be processed (toextract the information corresponding to the FEC operational parametersby which the subsequent FEC block is to be decoded), then the FEC blockmust be configured according to that extracted information, and then theFEC block is then actually decoded. This latency is existent for eachand every header and FEC block combination within this prior artapproach.

FIG. 1B is a diagram illustrating an embodiment of a prior art receiverarchitecture that may be employed to effectuate the approach of thecorresponding FIG. 1A described above. An input signal is first providedto a demodulator that performs any of the necessary demodulation of thereceived signal to get it into a format that is appropriate forsubsequent FEC decoding. In addition, the output of the demodulator issimultaneously provided to a parameter extraction functional block andto a FEC decoding functional block. The FEC decoding functional blockmust wait for the extraction of the FEC decoding parameters from theparameter extraction functional block before performing FEC decoding ina manner that is appropriate for the FEC block that immediately followsthe frame header from which the FEC decoding parameters have beenextracted. Again, it can be seen that this latency with respect to thisprior art approach to adjust the FEC operational parameters involvesprocessing the header that includes information corresponding to the FECoperational parameters, configuring the FEC functional block accordingto the most recently extracted FEC operational parameters, and thenperforming the actually decoding using the FEC decoding functional blockof the corresponding FEC block for which these FEC operationalparameters correspond.

Moreover, in this prior art approach, the frame headers are either notprotected by any error control code, or they are protected by adifferent FEC that protects the FEC blocks within the input signalstream. This different FEC that may be employed to protect the frameheaders is less powerful than the one for the actual data part of theinput signal stream. This type of prior art receiver suffers from manydeficiencies.

For example, it cannot operate at low SNR (Signal to Noise Ratio)because the frame headers are vulnerable to noise, as they are typicallynot protected by any error control code. Also, this prior art approachsuffers from the inherently slow and serial approach performed by thisprior art receiver architecture that includes a parameter extractionfunctional block that must be employed before performing any FECdecoding of the FEC blocks of the input signal stream that immediatelyfollow the frame header (e.g., the frame header that includes the FECdecoding parameters for that immediately following FEC block). Also inthe prior art, the information pertaining to the FEC parameters isembedded in the header before the FEC, and it uses a different codingthan the data part of the input signal stream or no coding at allthereby providing little protection.

As such, it is clear that there is a need in the art for a manner bywhich FEC operational parameters may be modified and adjusted on the fly(i.e., in real time) to effectuate higher performance within errorcorrectional coding communication systems.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the invention can be found in a receiver. Thereceiver includes a demodulator, an FEC (Forward Error Correction) chaindecoding functional block, and a parameter extraction functional block.The demodulator is operable to demodulate an input signal stream therebygenerating a demodulated signal stream that includes FEC (Forward ErrorCorrection) blocks. The FEC decoding chain functional block is operableto be configured to perform FEC decoding of a first plurality of FECblocks of the demodulated signal stream using a first plurality of FECdecoding parameters, and the FEC decoding chain functional block isoperable to detect a CP (Control Packet) when performing FEC decoding ofthe first plurality of FEC blocks of the demodulated signal stream.

The parameter extraction functional block is operable to extract asecond plurality of FEC decoding parameters from the CP. The parameterextraction functional block is operable to provide the second pluralityof FEC decoding parameters to the FEC decoding chain functional block,and the FEC decoding chain functional block is operable to bereconfigured to perform subsequent FEC decoding using the secondplurality of FEC decoding parameters.

The second plurality of FEC decoding parameters corresponds to a secondplurality of FEC blocks that is located a number of FEC blocks after theCP within the demodulated signal stream, and wherein the FEC decodingchain functional block performs FEC decoding of the second plurality ofFEC blocks of the demodulated signal stream using the second pluralityof FEC decoding parameters.

In certain embodiments, the FEC blocks of the demodulated signal streammay be implemented as QBs (Queue Blocks) such that each QB includes acorresponding plurality of TBs (Turbo Blocks). In such instances, theFEC decoding chain functional block performs FEC decoding on the QBsthereby generating MPEG (Moving Picture Experts Group) blocks, and theCP is a CP MPEG block.

The FEC decoding chain functional block may be implemented as includinga plurality of functional blocks such that operation of each functionalblock therein is governed by at least one parameter. The CP includes atleast one QB descriptor that contains a condensed representation of aplurality of parameters. The parameter extraction functional blockprocesses the QB descriptor to extract the second plurality of FECdecoding parameters from the CP, and the parameter extraction functionalblock provides the extracted second plurality of FEC decoding parametersback to the FEC decoding chain functional block to adjust at least oneparameter of the plurality of parameters thereby modifying the operationof at least one functional block of the plurality of functional blockswithin the FEC decoding chain functional block when decoding the secondplurality of FEC blocks. The types of QB descriptors that may beemployed may be a QB repeat descriptor or a QB sequence repeatdescriptor.

In some embodiments, the FEC decoding chain functional block may beimplemented as including a turbo decoder, a de-interleaver, a RS (ReedSolomon) decoder, a descrambler, and an MPEG packetizer. The operationof each of these operational functional blocks may be governed by one ormore corresponding parameters. As one example, one parameter that may beemployed to govern operation of the turbo decoder could be a turbo coderate, a number of TBs (Turbo Blocks) within the FEC blocks of thedemodulated signal stream, and/or a constellation scaling parameter. Theother operational functional blocks may have other correspondingparameters that govern their operation as well.

The FEC blocks that have been processed by the FEC decoding chainfunctional block can be provided to a MAC (Medium Access Controller).The FEC decoding chain functional block is operable to generate an errorflag when decoding the CP, and the error flag is operable to direct theparameter extraction functional block to process the CP to extract thesecond plurality of FEC decoding parameters from the CP.

The receiver is also operable to accommodate processing of FEC blocks ofan overlap queue. The overlap queue includes FEC blocks that are locatedbetween the CP and the second plurality of FEC blocks. The FEC decodingof the FEC blocks of the overlap queue can be performed according to anoverlap QB (Queue Block) descriptor, that is included within the CP andextracted there from, that contains a condensed representation of aplurality of parameters. Alternatively, the FEC decoding of the FECblocks of the overlap queue may simply be performed according to apredetermined plurality of parameters.

The receiver may be implemented within a wide variety of communicationdevices. Such a communication device may also be implemented within awide variety of communication systems including a one-way satellitecommunication system, a two-way satellite communication system, or anHDTV (High Definition Television) communication system.

The invention envisions any type of communication device that supportsthe functionality and/or processing described herein. Moreover, varioustypes of methods may be performed to support the functionality describedherein without departing from the scope and spirit of the invention aswell.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a diagram illustrating an embodiment of a prior art framestructure.

FIG. 1B is a diagram illustrating an embodiment of a prior art receiverarchitecture that may be employed in accordance with the invention.

FIG. 2 is a system diagram illustrating an embodiment of a one-waysatellite communication system that is built according to the invention.

FIG. 3 is a system diagram illustrating an embodiment of an HDTV (HighDefinition Television) communication system that is built according tothe invention.

FIG. 4 is a system diagram illustrating an embodiment of a satellitereceiver STB (Set Top Box) system that is built according to theinvention.

FIG. 5 is a diagram illustrating an embodiment of basic elements of atwo way satellite data system according to the invention.

FIG. 6A is a diagram illustrating example operational profiles that maybe employed according to the invention.

FIG. 6B is a diagram illustrating example modulation densities that maybe employed according to the invention.

FIG. 7 is a block diagram illustrating the processing blocks of anembodiment of a SG (Satellite Gateway), that incorporates the DownstreamAdaptive Modulation (DS-AM) functionality in accordance with variousaspects of the invention.

FIG. 8 is a diagram illustrating a block diagram of the AMFC (AdaptiveModulation Formatter & Controller) of the FIG. 7.

FIG. 9 is a block diagram illustrating the processing blocks of anembodiment of a SM (Satellite Modem), which incorporates the DS-AMfunctionality in accordance with various aspects of the invention.

FIG. 10 is a schematic block diagram illustrating a communication systemthat includes a plurality of base stations and/or access points, aplurality of wireless communication devices and a network hardwarecomponent in accordance with certain aspects of the invention.

FIG. 11 is a schematic block diagram illustrating a wirelesscommunication device that includes the host device and an associatedradio in accordance with certain aspects of the invention.

FIG. 12 is a diagram illustrating an alternative embodiment of awireless communication device that is constructed according to theinvention.

FIG. 13 is a diagram illustrating an embodiment of FEC (Forward ErrorCorrection) decoding chain functionality that may be implemented inaccordance with certain aspects of the invention.

FIG. 14 is a diagram illustrating an embodiment of parameters, which maybe output from a CP (Control Packet) processor, to govern 1 or more ofthe various functional blocks within an FEC decoding in accordance withcertain aspects of the invention.

FIG. 15 is a diagram illustrating an embodiment of a frame structurethat consists of FEC blocks with dynamic parameters that may beimplemented in accordance with certain aspects of the invention.

FIG. 16 is a diagram illustrating an embodiment of QB (Queue Block) thatmay be implemented in accordance with certain aspects of the invention.

FIG. 17A is a diagram illustrating an embodiment of the relationshipbetween latency and overlap queue that may be existent in accordancewith certain aspects of the invention.

FIG. 17B is a diagram illustrating another embodiment of therelationship between latency and overlap queue that may be existent inaccordance with certain aspects of the invention.

FIG. 18A is a diagram illustrating an embodiment of a receiverarchitecture employing dynamic parameters supported within a framestructure in accordance with certain aspects of the invention.

FIG. 18B is a diagram illustrating an embodiment of determination of aCP (Control Packet) MPEG (Moving Picture Experts Group) block from amonga plurality of MPEG blocks in accordance with certain aspects of theinvention.

FIG. 19A is a diagram illustrating an embodiment of determination ofindex usage (shown as Q index) within a CP (Control Packet) MPEG blockin accordance with certain aspects of the invention.

FIG. 19B is a diagram illustrating an embodiment of possible format of aCP MPEG block that may be employed in accordance with certain aspects ofthe invention.

FIG. 19C is a diagram illustrating another embodiment of possible formatof a CP MPEG block that may be employed in accordance with certainaspects of the invention.

FIG. 20 is a diagram illustrating an embodiment of general format of aQB (Queue Block) descriptor (employing 2 bytes) in accordance withcertain aspects of the invention.

FIG. 21 is a diagram illustrating an embodiment of a format of a QBrepeat descriptor (employing 2 bytes), and having 1 Q index, inaccordance with certain aspects of the invention.

FIG. 22 is a diagram illustrating an embodiment of a format of a QBsequence repeat descriptor (employing multiple bytes), and havingmultiple Q indices, in accordance with certain aspects of the invention.

FIG. 23 is a diagram illustrating an embodiment of CP (Control Packet)processor functionality that may be implemented in accordance withcertain aspects of the invention.

FIG. 24 is a flowchart illustrating an embodiment of a method for FEC(Forward Error Correction) decoding of a frame structure supportingdynamic FEC parameters that may be performed in accordance with certainaspects of the invention.

FIG. 25 is a flowchart illustrating an embodiment of a method for CP(Control Packet) processing that may be performed in accordance withcertain aspects of the invention.

FIG. 26 is a flowchart illustrating an embodiment of a method foradaptively changing frame structure and frame content based on operatingconditions in accordance with certain aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A novel solution of employing a parameter extraction functional blockthat follows the FEC (Forward Error Correction) decoding functionalblock is introduced. Information on the FEC decoding operationalparameters is embedded in the packets that come out of the FEC decodingfunctional block so that it is protected by the inherent errorcorrectional functionality and benefits provided by the FEC employedwithin the communication device. This packet that includes the FECoperational parameters is referred to as a CP (Control Packet). As oneparticular example, in the context where the communication deviceperforms FEC decoding on an MPEG (Moving Picture Experts Group (Note:this group is an International Standards Organisation/InternationalElectrotechnical Commission)) stream (e.g., an MPEG-2 transport streamin some instances), the CP is referred to as a CP MPEG block within theMPEG stream. Clearly, other types of communication systems and protocolscould also benefit from various aspects of the invention, andappropriately modified FEC block therein could also includes CP blocksin accordance with the scope and spirit of various aspects of theinvention. Generally speaking, this block may be referred to as a CP.However, as a reminder, in many of the embodiments to follow, a FECdecoding chain operates on an MPEG stream including a number of MPEGblocks, and the CP is referred to as a CP MPEG block in suchembodiments.

The CP specifies the FEC configurations for 1 or more FEC blocksfollowing it (i.e., not just a singular FEC block immediately followingthe CP). There are two issues that must be dealt with appropriately touse this advantageous approach. A first issue is that the FEC parametersthat are used to perform the FEC decoding of the CP must be knownbeforehand. This first issue may be dealt with quite easily byprogramming the FEC parameters for the CP as being of a default type(e.g., a predetermined type) that the FEC decoding functional block iseasily able to decode.

A second issue is the manner of how to deal with the FEC blocks thatfollow the CP that have already arrived in the FEC decoding functionalblock by the time the CP is fully decoded by the FEC decoding functionalblock because of the inherent latency of the FEC decoding functionalblock. This second issue (latency) may be resolved by the approachpresented below. The CPs specify the FEC configurations for the packetsthat are located some number of FEC blocks away from the CPs; there areintentionally left 1 or more FEC blocks after the CP for which the FECoperational parameters of the CP do not correspond. The distance betweenthe various CPs and the packets that are to be FEC decoded using the FECdecoding parameter specified in the CP can be selected depending on theintrinsic FEC latency of the FEC decoding functional block.

Various communication devices and communication system embodiments aredescribed initially below in which many of the various aspects of theinvention may be implemented. In general, any communication device thatperforms encoding and/or decoding of signals may benefit from theinvention. Generally speaking, the processing operations at thetransmitter end of a communication channel may be performed inaccordance with adaptive modulation and encoding, and the processingoperations at the receiver end of a communication channel may beperformed in accordance with FEC (Forward Error Correction) decodingwith dynamic parameters.

FIG. 2 is a system diagram illustrating an embodiment of a one-waysatellite communication system that is built according to the invention.A satellite transmitter is communicatively coupled to a satellite dishthat is operable to communicate with a satellite. The satellitetransmitter may also be communicatively coupled to a wired network. Thiswired network may include any number of networks including the Internet,proprietary networks, other wired networks, and/or WANs (Wide AreaNetworks). The satellite transmitter employs the satellite dish tocommunicate to the satellite via a wireless communication channel. Thesatellite is able to communicate with one or more satellite receivers(each oftentimes having a corresponding satellite dish). Each of thesatellite receivers may also be communicatively coupled to acorresponding display.

Here, the communication to and from the satellite may cooperatively beviewed as being a wireless communication channel, or each of thecommunication links to and from the satellite may be viewed as being twodistinct wireless communication channels.

For example, the wireless communication “channel” may be viewed as notincluding multiple wireless hops in one embodiment. In other multi-hopembodiments, the satellite receives a signal received from the satellitetransmitter (via its satellite dish), amplifies it, and relays it tosatellite receiver (via its satellite dish); the satellite receiver mayalso be implemented using terrestrial receivers such as satellitereceivers, satellite based telephones, and/or satellite based Internetreceivers, among other receiver types. In the case where the satellitereceives a signal received from the satellite transmitter (via itssatellite dish), amplifies it, and relays it, the satellite may beviewed as being a “transponder;” this is a multi-hop embodiment. Inaddition, other satellites may exist that perform both receiver andtransmitter operations in cooperation with the satellite. In this case,each leg of an up-down transmission via the wireless communicationchannel would be considered separately.

In whichever embodiment, the satellite communicates with the satellitereceiver. The satellite receiver may be viewed as being a mobile unit incertain embodiments (employing a local antenna); alternatively, thesatellite receiver may be viewed as being a satellite earth station thatmay be communicatively coupled to a wired network in a similar manner inwhich the satellite transmitter may also be communicatively coupled to awired network.

The satellite transmitter is operable to encode information (using anencoder) in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention toassist in generating a signal that is to be launched into thecommunication channel coupling the satellite transmitter and thesatellite receiver. The satellite receiver is operable to decode asignal (using a decoder) received from the communication channel in amanner in accordance with the functionality and/or processing of atleast some of the various aspects of the invention. This diagram showsone embodiment where one or more of the various aspects of the inventionmay be found.

FIG. 3 is a system diagram illustrating an embodiment of an HDTV (HighDefinition Television) communication system that is built according tothe invention. An HDTV transmitter is communicatively coupled to atower. The HDTV transmitter, using its tower, transmits a signal to alocal tower dish via a wireless communication channel. The local towerdish may communicatively couple to an HDTV STB (Set Top Box) receivervia a coaxial cable. The HDTV STB receiver includes the functionality toreceive the wireless transmitted signal that has been received by thelocal tower dish. This functionality may include any transformationand/or down-converting that may be needed to accommodate for anyup-converting that may have been performed before and duringtransmission of the signal from the HDTV transmitter and itscorresponding tower to transform the signal into a format that iscompatible with the communication channel across which it istransmitted. For example, certain communication systems step a signalthat is to be transmitted from a baseband signal to an IF (IntermediateFrequency) signal, and then to a carrier frequency signal beforelaunching the signal into a communication channel. Alternatively, somecommunication systems perform a conversion directly from baseband tocarrier frequency before launching the signal into a communicationchannel. In whichever case is employed within the particular embodiment,the HDTV STB receiver is operable to perform any down-converting thatmay be necessary to transform the received signal to a baseband signalthat is appropriate for demodulating and decoding to extract theinformation there from.

The HDTV STB receiver is also communicatively coupled to an HDTV displaythat is able to display the demodulated and decoded wireless transmittedsignals received by the HDTV STB receiver and its local tower dish. TheHDTV STB receiver may also be operable to process and output standarddefinition television signals as well. For example, when the HDTVdisplay is also operable to display standard definition televisionsignals, and when certain video/audio is only available in standarddefinition format, then the HDTV STB receiver is operable to processthose standard definition television signals for use by the HDTVdisplay.

The HDTV transmitter (via its tower) transmits a signal directly to thelocal tower dish via the wireless communication channel in thisembodiment. In alternative embodiments, the HDTV transmitter may firstreceive a signal from a satellite, using a satellite earth station thatis communicatively coupled to the HDTV transmitter, and then transmitthis received signal to the local tower dish via the wirelesscommunication channel. In this situation, the HDTV transmitter operatesas a relaying element to transfer a signal originally provided by thesatellite that is ultimately destined for the HDTV STB receiver. Forexample, another satellite earth station may first transmit a signal tothe satellite from another location, and the satellite may relay thissignal to the satellite earth station that is communicatively coupled tothe HDTV transmitter. In such a case the HDTV transmitter includetransceiver functionality such that it may first perform receiverfunctionality and then perform transmitter functionality to transmitthis received signal to the local tower dish.

In even other embodiments, the HDTV transmitter employs its satelliteearth station to communicate to the satellite via a wirelesscommunication channel. The satellite is able to communicate with a localsatellite dish; the local satellite dish communicatively couples to theHDTV STB receiver via a coaxial cable. This path of transmission showsyet another communication path where the HDTV STB receiver maycommunicate with the HDTV transmitter.

In whichever embodiment and by whichever signal path the HDTVtransmitter employs to communicate with the HDTV STB receiver, the HDTVSTB receiver is operable to receive communication transmissions from theHDTV transmitter and to demodulate and decode them appropriately.

The HDTV transmitter is operable to encode information (using anencoder) in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention toassist in generating a signal that is to be launched into thecommunication channel coupling the HDTV transmitter and the HDTV STBreceiver. The HDTV STB receiver is operable to decode a signal (using adecoder) received from the communication channel in a manner inaccordance with the functionality and/or processing of at least some ofthe various aspects of the invention. This diagram shows yet anotherembodiment where one or more of the various aspects of the invention maybe found.

FIG. 4 is a system diagram illustrating an embodiment of a satellitereceiver STB (Set Top Box) system that is built according to theinvention. The satellite receiver STB system includes an advancedmodulation satellite receiver that is implemented in an all digitalarchitecture. Moreover, the advanced modulation satellite receiver maybe implemented within a single integrated circuit in some embodiments.The satellite receiver STB system includes a satellite tuner thatreceives a signal via the L-band (e.g., within the frequency rangebetween 390-1550 MHz (Mega-Hertz) in the ultrahigh radio frequencyrange). The satellite tuner extracts I, Q (In-phase, Quadrature)components from a signal received from the L-band and provides them tothe advanced modulation satellite receiver. The advanced modulationsatellite receiver includes a decoder.

As within other embodiments that employ a decoder, the decoder isoperable to decode a signal received from a communication channel towhich the advanced modulation satellite receiver is coupled in a mannerin accordance with the functionality and/or processing of at least someof the various aspects of the invention. This diagram shows yet anotherembodiment where one or more of the various aspects of the invention maybe found.

The advanced modulation satellite receiver may be implemented tocommunicatively couple to an HDTV MPEG-2 (Motion Picture Expert Group,level 2) transport de-mux, audio/video decoder and display engine. Theadvanced modulation satellite receiver and the HDTV MPEG-2 transportde-mux, audio/video decoder and display engine communicatively couple toa host CPU (Central Processing Unit). The HDTV MPEG-2 transport de-mux,audio/video decoder and display engine also communicatively couples to amemory module and a conditional access functional block. The HDTV MPEG-2transport de-mux, audio/video decoder and display engine provides HD(High Definition) video and audio output that may be provided to an HDTVdisplay.

The advanced modulation satellite receiver may be implemented as asingle-chip digital satellite receiver supporting the decoder thatoperates in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention. Theadvanced modulation satellite receiver is operable to receivecommunication provided to it from a transmitter device that includes anencoder as well.

FIG. 5 is a diagram illustrating an embodiment of basic elements of atwo way satellite data system according to the invention. A SG(Satellite Gateway) with a baseband modulator/demodulator receives datafrom a network, such as the Internet, or some other WAN (Wide AreaNetwork). At the transmitting end of the communication system, data isassembled (e.g., encoded and modulated) into an appropriate format inaccordance with a predetermined format in the SG and is then provided toa transceiver communicatively coupled thereto. This format of dataassembly may be performed in accordance with any of a variety of meansincluding any of the various the DOCSIS (Data Over Cable ServiceInterface Specification) architectures. This transceiver is operable toperform certain functions necessary for transmitting the data using thesatellite dish, up to the satellite and down to one or more SMs(Satellite Modems) over a downstream communication channel. Thedownstream signal is received by the satellite dish at the user end ofthe communication channel, processed by the transceiver communicativelycoupled thereto, and demodulated and subsequently decoded by the SM. TheSM transmits data, generated by a CPE (Customer Premise(s) Equipment),shown as a user device/subscriber, back to the SG over the upstreamcommunication channel (via the satellite and the corresponding satellitedishes and transceivers at each end of the communication channel) usinga format recognized by the SG.

The SG is operable to encode information (using an encoder) in a mannerin accordance with the functionality and/or processing of at least someof the various aspects of the invention to assist in generating a signalthat is to be launched into the communication channel coupling thesatellite dish and the corresponding transceiver. The SM is operable todecode a signal (using a decoder) received from the communicationchannel in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention.This diagram shows yet another embodiment where one or more of thevarious aspects of the invention may be found.

Generally speaking, the communication sent downstream from the SG to theSM is performed using a relatively higher order operational profile, andthe communication sent upstream from the SG to the SM is performed usinga relatively lower order operational profile. In some instances, the SMend is operable to asses various indicia corresponding to the operatingconditions of the communication channel and to provide that informationback to the SG. In response to this information provided to the SG endof the communication channel, the SG can adaptively modify the variousparameters within its operational profile. For example, the SG canmodify, in real time, any 1 or more of the various operationalparameters within the downstream operational profile.

FIG. 6A is a diagram illustrating example operational profiles that maybe employed according to the invention. A spectrum of operationalprofiles may be used to service both the upstream and downstreamtransmission within a communication system. Generically speaking, ahigher order operational profile may be used to service downstreamcommunications, and a lower order operational profile may be used toservice upstream communications.

The higher order profile may be viewed as having a relatively highercode rate, a relatively higher modulator density, relatively weak FEC(Forward Error Correction), relatively higher operational speed, andother parameters as required or desired. The lower order profile may beviewed as having a relatively lower code rate, a relatively lowermodulator density (when compared to the higher order modulator densityof the higher order profile), relatively powerful FEC (when compared tothe weaker FEC of the higher order profile), relatively loweroperational speed, and other parameters as required or desired.Generally speaking, the parameters of the lower order operationalprofile are much more robust than the parameters of the higher orderoperational profile.

FIG. 6B is a diagram illustrating example modulation densities that maybe employed according to the invention. The spectrum of modulationdensities involves higher order modulation densities and lower ordermodulation densities. For example, the spectrum of modulation densitiesranges from 1024 QAM (Quadrature Amplitude Modulation), 256 QAM, 64 QAM,16 QAM, QPSK (Quadrature Phase Shift Keying), and BPSK (Binary PhaseShift Keying). Other modulation schemes could similarly be employed andarranged in an increasing/decreasing order of density without departingfrom the scope and spirit of the invention. The higher order modulationdensities may be viewed as including the 1024 QAM and 256 QAM, and thelower order modulation densities may be viewed as including the 16 QAM,QPSK, and BPSK. In some embodiments, a higher order modulation densitymay be viewed as including only 16 QAM, and a lower order modulationdensity may be viewed as including only QPSK.

Generically speaking, a higher order modulation density may be used toservice downstream communications, and a lower higher order modulationdensity may be used to service upstream communications.

These diagrams of FIG. 6A and FIG. 6B show just some of the possiblevariations of operational parameters that may be employed, andadaptively modified, when operating within a communication system inaccordance with the invention. For example, certain of these variousoperational parameters may be modified based on the operating conditionsof the communication system.

FIG. 7 is a block diagram illustrating the processing blocks of anembodiment of a SG (Satellite Gateway), that incorporates the DownstreamAdaptive Modulation (DS-AM) functionality in accordance with variousaspects of the invention. This diagram includes the various processingblocks of an SG, along with the processing blocks of the correspondingtransceiver communicatively coupled thereto. Data from a network, suchas the Internet or some other WAN (Wide Area Network), is transmittedbetween the network and the gateway SG MAC. This SG MAC may beimplemented as an SG DOCSIS MAC in certain embodiments. The data isformatted in accordance with the protocol employed therein (e.g., theDOCSIS protocol in DOCSIS type systems). This protocol uses an MPEG(Moving Picture Experts Group) format in the “downstream transmissionconvergence sublayer” that serves as the interface between the MAC andPHY (physical layer). Each of the various MPEG specifications ispublicly available and is incorporated herein by this reference for allpurposes.

The downstream MPEG data stream that is output from the SG MACprocessing block is provided to an AMFC (Adaptive Modulation andFormatter & Controller) stage that receives and processes theappropriately encapsulated traffic received from the SG MAC processingblock. The modulation type and/or FEC parameters employed by the AMFCmay be adaptively modified based on the operating conditions of theoverall communication system. An interface could be a MPEG data streamcompliant with the downstream transmission convergence sub-layer, or itcould have an alternative format. The SG also includes a variableencoding & modulation stage, which is a modulator that is capable ofhaving its modulation type and FEC encoding parameters dynamicallycontrolled on a QB (Queue Block) by QB basis.

The appropriately encoded and modulated MPEG stream is then up convertedand filtered, and then fed into a high PA (Power Amplifier) by thetransceiver. This signal is transmitted continuously in a singlefrequency band, through a satellite and received by one or moresubscriber SMs.

The SG also receives (e.g., via a satellite dish) the upstream signaltransmitted by one or more subscriber SMs of the communication system.The signal is filtered and down converted back to baseband usingappropriate demodulation and decoding parameters to recover the upstreamdata stream.

FIG. 8 is a diagram illustrating a block diagram of the AMFC (AdaptiveModulation Formatter & Controller) of the FIG. 7.

The host controller receives downstream signal quality information foreach of the particular SMs over the upstream channel. The SM is anembodiment of a satellite modem that is operable to receive and decodedownstream transmissions from the SG that have been adaptively modulatedand encoded using the DS-AM functionality (i.e., method and apparatus)of the invention. The SM is discussed in more detail below.

The downstream signal quality for each SM can be based on, for example,the SNR (Signal to Noise Ratio), packet or code word error rate, orother parameters defining signal quality. The SM can be made to monitorthat information continuously, so that any changes in the signal qualitymay be dynamically reflected at the SG and communicated thereto from theSM. Different sets of operational profiles (including values for coderate, modulation density and/or modulation type, FEC type, and/or FECrate) are defined spanning the range of expected signal quality.

An example of a set of four profiles based on SNR as a signal qualitymeasurement is shown below in Table 1. As Table 1 illustrates, theprofiles trade-off higher throughput (shown as higher bandwidthefficiency in Table 1) for higher required signal quality. Clearly,Table 1 is only a hypothetical example. Other operational profiles withdifferent performance characteristics and different transmissionparameters could be specified while staying within the scope of theinvention.

TABLE 1 Example Transmission Parameter Profiles for DS-AM BandwidthEfficiency Required Profile Modulation FEC Rate [bits/sec/Hz] SNR 1 QPSK½ 1.0 3.0 2 QPSK ¾ 1.5 6.0 3 8 PSK ⅔ 2.0 9.0 4 16 QAM ¾ 3.0 12.0 

The host controller assigns each of the different profiles to one ormore of the queues. Put another way, each packet queue is associatedwith a unique modulation order and/or FEC code rate that defines athroughput rate in the form of bandwidth efficiency (i.e., bits persecond per 1 Hz of bandwidth). Traffic for a given SM is then assignedto a specific queue or set of the queues having an assigned operationalprofile that is appropriate for the downstream quality informationprovided by that SM. Sufficient information is associated with eachpacket to allow it to be assigned to the proper queue. For example, inthe DOCSIS context, the packets can be assigned to the different queuesby means of the DOCSIS DA (Destination Address), SID (Service ID), orany other unique identifier that is available with the DOCSIS protocol.

The AMFC receives the data stream from the SG MAC. In the DOCSIScontext, DOCSIS packets destined for individual SMs are parsed andplaced in their assigned packet queues. One possible format for the datainterface between the SG MAC and the AMFC is an MPEG format.

FIG. 9 is a block diagram illustrating the processing blocks of anembodiment of a SM (Satellite Modem), which incorporates the DS-AMfunctionality in accordance with various aspects of the invention. Aspreviously discussed, the SMs must be able to decode and demodulate theadaptively modulated stream. This diagram is a block diagramillustrating the processing blocks of an embodiment of a SM, whichincorporates the DS-AM method and apparatus of various aspects of theinvention. The adaptive demodulation and decoding block decodes thePHY-MAP message sent from the SG. This message is used to determine theproper demodulation and decoding parameters to use during the propertime intervals (i.e. for each QB). The SM is operable to decode anddemodulate the most robust data packet queue to extract the timestampand MAC management messages sent to all SMs.

The SMs use the MAC management messages to set up an upstream channel tothe SG. SM uses this upstream channel to send downstream signal qualitymetrics to the host of the SG. This could be implemented as part of theranging and registration process common to these systems or as separateMAC messages. Based on its signal quality, each SM identifies themaximum downstream throughput rate that it can handle with acceptablefidelity, and decodes data received from the packet queue assigned tohandle that throughput rate as well as from any queue having a morerobust profile. If any packet queue cannot be demodulated by the SM withappropriate fidelity, the SM fills output MPEG frames corresponding tothat queue with null MPEG frames, or otherwise blanks the data sent tothe SM DOCSIS MAC. The decoded stream is transmitted to the SM DOCSISMAC over the appropriate output port.

The SG uses the PHY-MAP for flexible and optimized assignment of QBs tothe downstream. As channel conditions or traffic loading changes, thePHY-MAP can be dynamically adjusted to optimize efficiency. Decoding allpossible queues by the SM assures that all SMs will receive PHY-MAPmessages and multi-cast traffic over the packet queue having the mostrobust modulation and encoding. It also permits the SG the flexibilityto assign traffic destined for a given SM to the queue having thehighest possible throughput, or to any of the more robust queues.

FIG. 10 is a schematic block diagram illustrating a communication systemthat includes a plurality of base stations and/or access points, aplurality of wireless communication devices and a network hardwarecomponent in accordance with certain aspects of the invention. Thewireless communication devices may be laptop host computers, PDA(Personal Digital Assistant) hosts, PC (Personal Computer) hosts and/orcellular telephone hosts. The details of any one of these wirelesscommunication devices is described in greater detail with reference toFIG. 11 below.

The BSs (Base Stations) or APs (Access Points) are operably coupled tothe network hardware via the respective LAN (Local Area Network)connections. The network hardware, which may be a router, switch,bridge, modem, system controller, etc., provides a WAN (Wide AreaNetwork) connection for the communication system. This WAN connectionmay couple to the Internet in some embodiments. Each of the BSs or APshas an associated antenna or antenna array to communicate with thewireless communication devices in its area. Typically, the wirelesscommunication devices register with a particular BS or AP to receiveservices from the communication system. For direct connections (i.e.,point-to-point communications), wireless communication devicescommunicate directly via an allocated channel.

Typically, BSs are used for cellular telephone systems and like-typesystems, while APs are used for in-home or in-building wirelessnetworks. Regardless of the particular type of communication system,each wireless communication device includes a built-in radio and/or iscoupled to a radio. The radio includes a highly linear amplifier and/orprogrammable multi-stage amplifier to enhance performance, reduce costs,reduce size, and/or enhance broadband applications.

FIG. 11 is a schematic block diagram illustrating a wirelesscommunication device that includes the host device and an associatedradio in accordance with certain aspects of the invention. For cellulartelephone hosts, the radio is a built-in component. For PDA (PersonalDigital Assistant) hosts, laptop hosts, and/or personal computer hosts,the radio may be built-in or an externally coupled component.

As illustrated, the host device includes a processing module, memory,radio interface, input interface and output interface. The processingmodule and memory execute the corresponding instructions that aretypically done by the host device. For example, for a cellular telephonehost device, the processing module performs the correspondingcommunication functions in accordance with a particular cellulartelephone standard or protocol.

The radio interface allows data to be received from and sent to theradio. For data received from the radio (e.g., inbound data), the radiointerface provides the data to the processing module for furtherprocessing and/or routing to the output interface. The output interfaceprovides connectivity to an output display device such as a display,monitor, speakers, etc., such that the received data may be displayed orappropriately used. The radio interface also provides data from theprocessing module to the radio. The processing module may receive theoutbound data from an input device such as a keyboard, keypad,microphone, etc., via the input interface or generate the data itself.For data received via the input interface, the processing module mayperform a corresponding host function on the data and/or route it to theradio via the radio interface.

The radio includes a host interface, a digital receiver processingmodule, an ADC (Analog to Digital Converter), a filtering/gain module,an IF (Intermediate Frequency) mixing down conversion stage, a receiverfilter, an LNA (Low Noise Amplifier), a transmitter/receiver switch, alocal oscillation module, memory, a digital transmitter processingmodule, a DAC (Digital to Analog Converter), a filtering/gain module, anIF mixing up conversion stage, a PA (Power Amplifier), a transmitterfilter module, and an antenna. The antenna may be a single antenna thatis shared by the transmit and the receive paths as regulated by theTx/Rx (Transmit/Receive) switch, or may include separate antennas forthe transmit path and receive path. The antenna implementation willdepend on the particular standard to which the wireless communicationdevice is compliant.

The digital receiver processing module and the digital transmitterprocessing module, in combination with operational instructions storedin memory, execute digital receiver functions and digital transmitterfunctions, respectively. The digital receiver functions include, but arenot limited to, digital IF (Intermediate Frequency) to basebandconversion, demodulation, constellation de-mapping, decoding, and/ordescrambling. The digital transmitter functions include, but are notlimited to, scrambling, encoding, constellation mapping, modulation,and/or digital baseband to IF conversion.

Similarly to other embodiments that employ an encoder and a decoder (orperform encoding and decoding), the encoding operations that may beperformed by the digital transmitter processing module may beimplemented in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention toassist in generating a signal that is to be launched into thecommunication channel coupling to the wireless communication device.Analogously, the decoding operations of the operations that may beperformed by the digital transmitter processing module may beimplemented in a manner in accordance with the functionality and/orprocessing of at least some of the various aspects of the invention. Forexample, the encoding operations performed by the digital transmitterprocessing module may be performed using adaptive modulation andencoding functionality as described and presented herein, and thedecoding operations that may be performed by the digital receiverprocessing module may be performed using the FEC with dynamic parametersas also described and presented herein.

The digital receiver and transmitter processing modules may beimplemented using a shared processing device, individual processingdevices, or a plurality of processing devices. Such a processing devicemay be a microprocessor, micro-controller, DSP (Digital SignalProcessor), microcomputer, CPU (Central Processing Unit), FPGA (FieldProgrammable Gate Array), programmable logic device, state machine,logic circuitry, analog circuitry, digital circuitry, and/or any devicethat manipulates signals (analog and/or digital) based on operationalinstructions. The memory may be a single memory device or a plurality ofmemory devices. Such a memory device may be a ROM (Read Only Memory),RAM (Random Access Memory), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. It is noted that when either of the digitalreceiver processing module or the digital transmitter processing moduleimplements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory storingthe corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry.

In operation, the radio receives outbound data from the host device viathe host interface. The host interface routes the outbound data to thedigital transmitter processing module, which processes the outbound datain accordance with a particular wireless communication standard (e.g.,IEEE 802.11, Bluetooth®, etc.) to produce digital transmission formatteddata. The digital transmission formatted data is a digital base-bandsignal or a digital low IF signal, where the low IF typically will be inthe frequency range of one hundred kHz (kilo-Hertz) to a few MHz(Mega-Hertz).

The DAC converts the digital transmission formatted data from thedigital domain to the analog domain. The filtering/gain module filtersand/or adjusts the gain of the analog signal prior to providing it tothe IF mixing stage. The IF mixing stage converts the analog baseband orlow IF signal into an RF signal based on a transmitter local oscillationprovided by local oscillation module. The PA amplifies the RF signal toproduce outbound RF signal, which is filtered by the transmitter filtermodule. The antenna transmits the outbound RF signal to a targeteddevice such as a base station, an access point and/or another wirelesscommunication device.

The radio also receives an inbound RF signal via the antenna, which wastransmitted by a BS, an AP, or another wireless communication device.The antenna provides the inbound RF signal to the receiver filter modulevia the Tx/Rx switch, where the Rx filter bandpass filters the inboundRF signal. The Rx filter provides the filtered RF signal to the LNA,which amplifies the signal to produce an amplified inbound RF signal.The LNA provides the amplified inbound RF signal to the IF mixingmodule, which directly converts the amplified inbound RF signal into aninbound low IF signal or baseband signal based on a receiver localoscillation provided by local oscillation module. The down conversionmodule provides the inbound low IF signal or baseband signal to thefiltering/gain module. The filtering/gain module filters and/or gainsthe inbound low IF signal or the inbound baseband signal to produce afiltered inbound signal.

The ADC converts the filtered inbound signal from the analog domain tothe digital domain to produce digital reception formatted data. In otherwords, the ADC samples the incoming continuous time signal therebygenerating a discrete time signal (e.g., the digital reception formatteddata). The digital receiver processing module decodes, descrambles,demaps, and/or demodulates the digital reception formatted data torecapture inbound data in accordance with the particular wirelesscommunication standard being implemented by radio. The host interfaceprovides the recaptured inbound data to the host device via the radiointerface.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 11 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the digital receiver processing module, thedigital transmitter processing module and memory may be implemented on asecond integrated circuit, and the remaining components of the radio,less the antenna, may be implemented on a third integrated circuit. Asan alternate example, the radio may be implemented on a singleintegrated circuit. As yet another example, the processing module of thehost device and the digital receiver and transmitter processing modulesmay be a common processing device implemented on a single integratedcircuit. Further, the memories of the host device and the radio may alsobe implemented on a single integrated circuit and/or on the sameintegrated circuit as the common processing modules of processing moduleof the host device and the digital receiver and transmitter processingmodule of the radio.

FIG. 12 is a diagram illustrating an alternative embodiment of awireless communication device that is constructed according to theinvention. This embodiment of a wireless communication device includesan antenna that is operable to communicate with any 1 or more otherwireless communication devices. An antenna interface communicativelycouples a signal to be transmitted from the wireless communicationdevice or a signal received by the wireless communication device to theappropriate path (be it the transmit path or the receive path).

A radio front end includes receiver functionality and transmitterfunctionality. The radio front end communicatively couples to ananalog/digital conversion functional block. The radio front endcommunicatively couples to a modulator/demodulator, and the radio frontend communicatively couples to a encoder/decoder.

Along the Receive Path:

The receiver functionality of the front end includes a LNA (Low NoiseAmplifier)/filter. The filtering performed in this receiverfunctionality may be viewed as the filtering that is limiting to theperformance of the device, as also described above. The receiverfunctionality of the front end performs any down-converting that may berequiring (which may alternatively include down-converting directly fromthe received signal frequency to a baseband signal frequency). Thegeneral operation of the front end may be viewed as receiving acontinuous time signal, and performing appropriate filtering and anydown conversion necessary to generate the baseband signal. Whichevermanner of down conversion is employed, a baseband signal is output fromthe receiver functionality of the front end and provided to an ADC(Analog to Digital Converter) that samples the baseband signal (which isalso a continuous time signal, though at the baseband frequency) andgenerates a discrete time signal baseband signal (e.g., a digital formatof the baseband signal); the ADC also extracts and outputs the digitalI, Q (In-phase, Quadrature) components of the discrete time signalbaseband signal.

These I, Q components are provided to a demodulator portion of themodulator/demodulator where any modulation decoding/symbol mapping isperformed where the I, Q components of the discrete time signal basebandsignal. The appropriate I, Q components are then mapped to anappropriate modulation (that includes a constellation and correspondingmapping). Examples of such modulations may include BPSK (Binary PhaseShift Key), QPSK (Quadrature Phase Shift Key), 8 PSK (8 Phase ShiftKey), 16 QAM (16 Quadrature Amplitude Modulation), and even higher ordermodulation types. These demodulated symbols are then provided to adecoder portion of the encoder/decoder where FEC decoding using dynamicparameters is performed in accordance with the scope and spirit ofvarious aspects of the invention. Additional details are also providedbelow with respect to the FEC decoding functionality illustrated in thisand other embodiments.

Along the Transmit Path:

Somewhat analogous and opposite processing is performed in the transmitpath when compared to the receive path. Information bits that are to betransmitted are encoded using an encoder of the encoder/decoder. Theseencoded bits are provided to a modulator of the modulator/demodulatorwhere modulation encoding/symbol mapping may be performed according tothe modulation of interest. It is also noted that the encoder isoperable to perform adaptive encoding, and the modulator is operable toperform adaptive modulation in accordance with the scope and spirit ofvarious aspects of the invention.

These now I, Q components of the symbols are then passed to a DAC(Digital to Analog Converter) of the analog/digital conversionfunctional block to transform the I, Q components into a continuous timetransmit signal (e.g., an analog signal). Then, the continuous timetransmit signal is passed to a transmit driver that performs anynecessary up-converting/modification to the continuous time transmitsignal (e.g., amplification and/or filtering) to comport it to theappropriate form for the communication channel over which the signal isto be transmitted. Once this continuous time transmit signal hasundergone all of this appropriate processing, it may then be transmittedto another communication device via the antenna.

As within other embodiments that employ an encoder and a decoder, theencoder of this wireless communication device may be implemented toencode information in a manner in accordance with the functionalityand/or processing of at least some of the various aspects of theinvention to assist in generating a signal that is to be launched intothe communication channel coupling to the wireless communication device.The decoder of the wireless communication device may be implemented todecode a received signal in a manner in accordance with thefunctionality and/or processing of at least some of the various aspectsof the invention. This diagram shows yet another embodiment where one ormore of the various aspects of the invention may be found.

FIG. 13 is a diagram illustrating an embodiment of FEC (Forward ErrorCorrection) decoding chain functionality that may be implemented inaccordance with certain aspects of the invention. This diagram showssome of the various functional blocks that may be found within an FECdecoding chain (which may alternatively be referred to as an FEC decoderand/or an FEC decoding functional block). An input signal is provided toa demodulator. This input signal that is provided to the demodulator maybe viewed as being a signal that is provided from a pre-processingportion of such a communication device that includes the FEC decodingfunctionality with dynamic parameters as described herein. These variousfunctional blocks within the FEC decoding chain illustrate one possibleembodiment of functional blocks that may be employed; however,variations thereof may also employed without departing from the scopeand spirit of the invention.

An input signal is provided to a demodulator; this input signal may beviewed as being a digital signal that is generated from a receivedcontinuous time signal that has been appropriately filtered,down-converted, digitally sampled, and so on. The demodulator generatesa QB (Queue Block) stream that includes a plurality of TBs (TurboBlocks). Each of the QBs includes a number of TBs. This number of TBsper QB may be selected by a designer of such a device. Variousembodiments are also described below indicating some of the possiblemeans by which the QB stream may be viewed in terms of the included TBs.

The QB stream output from the demodulator is passed to an FEC decodingchain functional block. This FEC decoding chain functional block mayalternatively be represented as an FEC decoder without departing fromthe scope and spirit of the invention. The QB stream enters the FECdecoding chain functional block and is initially provided to a turbodecoder that performs iterative decoding processing in an effort to makebest estimates of the information bits for each of the symbols (foundwithin the various TBs of the corresponding QBs) included within thereceived signal on which a communication device including this FECdecoding chain functionality is implemented.

These turbo decoded TBs (of the corresponding QBs of the QB stream) arethen passed to a de-interleaver (shown as π⁻¹). The turbo decoded TBsare then de-interleaved and passed to an RS (Reed Solomon) decoder,which is sometimes referred to as an outer block decoder. After passingthrough the RS decoder, the signal is passed through a descrambler. Thedescrambler output is passed to an MPEG packetizer that arranges thesignal into an MPEG stream. This MPEG stream may be implemented as anMPEG-2 transport stream in some embodiments. The MPEG stream may beviewed as a successive series of MPEG blocks. The manner by which FECdecoding is to be performed on subsequent MPEG blocks is governed by CP(Control Packet) information that is extracted from a particular type ofMPEG block, namely, a CP MPEG block (that includes CP information).

Each of the various functional blocks within the FEC decoding chainfunctional block includes 1 or more operational parameters (which may bereferred to as “FEC decoding parameters” or simply as “parameters” forbrevity hereinafter). For example, the turbo decoder operates accordingto 1 or more turbo decoder parameters; the de-interleaver operatesaccording to 1 or more turbo de-interleaver parameters; the RS decoderoperates according to 1 or more RS decoder parameters; and thedescrambler operates according to 1 or more descrambler parameters. Someexamples of various types of parameters for each of these functionalblocks within the FEC decoding chain functional block are described andpresented with respect to the following diagram.

The MPEG stream that is generated by the FEC decoding chain functionalblock is passed to a MAC (Medium Access Controller) and/or other higherprotocol layers within the communication device in which the FECdecoding chain functional block is implemented. In addition, this sameMPEG stream is also passed to a CP (Control Packet) processor. The CPprocessor is operable to extract 1 or more parameters from a CP MPEGblock (that is within the MPEG stream output from the FEC decoding chainfunctional block) and to provide those extracted parameters to theappropriate functional blocks within the FEC decoding chain functionalblock. For example, the extracted parameter may include any 1 or moreparameters to adjust the manner by which 1 or more of the functionalblocks within the FEC decoding chain functional block operate. Thismeans of extracting the FEC parameters from an actual FEC block (i.e., aCP MPEG block in this particular embodiment) ensures that the FECparameters that are provided to a receiver end communication device areprotected by the FEC. In addition, the same decoding functionality thatis operable to operate on the actual MPEG blocks received by such acommunication device is also employed to process the CP MPEG blocks thatinclude the FEC parameters. These extracted FEC parameters allow for theadjustment of 1 or more of the parameters that govern the operation of 1or more of the functional blocks within the FEC decoding chainfunctional block. This allows for adaptive modulation of the FECparameters of the FEC decoding chain functional block on the fly (i.e.,in real time) in response to changes in the operating conditions of thecommunication device and/or the communication system in which thecommunication device is situated and operating.

FIG. 14 is a diagram illustrating an embodiment of parameters, which maybe output from a CP (Control Packet) processor, to govern 1 or more ofthe various functional blocks within an FEC decoding in accordance withcertain aspects of the invention. This diagram provides a non-exhaustivelisting of some of the possible parameters that may be employed toadjust and govern the operation of 1 or more of the functional blockswithin the FEC decoding chain functional block.

Looking at the turbo decoder parameters, these parameters may includeany number of various parameters by which the turbo code is employed.For example, this may include turbo code rate, the number (#) of TBs(Turbo Blocks) within each of the corresponding FEC blocks, theconstellation scaling (i.e., in terms of the I, Q of constellationpoints within the 2 dimensional I, Q graph of the correspondingconstellation shape and modulation type) that is employed, and any otherturbo decoder parameter as well. Looking at the de-interleaver (π⁻¹)parameters, these may include the interleaving depth (shown as π depth),interleaving block length (shown as π block length), and any otherde-interleaver parameter as well. Looking at the RS (Reed Solomon)decoder parameters, these may include T_(c) (which is known in the RSdecoding context as the number of errors that the RS code canaccommodate without failing), the RS b block length, the number of RSblocks), and any other RS decoder parameter as well. Looking at thede-scrambler parameters, these may include the number of MPEG blocksthat are to be operated on when performing any descrambling operation aswell as any other descrambler parameter as well.

Generally speaking, CP MPEG block may include information correspondingto any 1 or more of these parameters depicted within this diagram sothat the operation of the various functional blocks within the FECdecoding functional block may be adaptively modified in real time toaccommodate any changes in the operating conditions of the communicationdevice in which the FEC decoding functional block is implemented or thecommunication system in which such a communication device isimplemented. Clearly, this list is non-exhaustive, and otheruser-defined parameters could also be added to (or taken from this list)without departing from the scope and spirit of the invention. Moreover,in particular embodiments whose individual functional blocks within aFEC decoding chain functional block differ from those functional blocksshown in the various embodiments herein, parameters corresponding tothose different functional blocks could be added to such a list. Suchnewly added parameters could also be modified in real time in responseto any changes of the operating conditions described above in accordancewith the invention.

FIG. 15 is a diagram illustrating an embodiment of a frame structurethat consists of FEC blocks with dynamic parameters that may beimplemented in accordance with certain aspects of the invention. Thisdiagram shows how a generic CP includes information that is used tospecify the FEC decoding parameters for packets (shown as groups of FECblocks) that are some number of blocks away from the CP. It is notedthat the minimum distance (or minimum number) of FEC blocks between theCP and the 1^(st) FEC block for which the parameters of the CPcorrespond is typically selected based on the intrinsic FEC latency ofthe FEC decoding functional block. In an ideal situation where an FECdecoding functional block has no latency at all, then the FEC parametersof the CP could very well then apply to govern the FEC decoding of anFEC block immediately following the CP. However, since such an idealdevice does not exist, the various operational aspects of the inventionprovide for a novel means by which the FEC parameters may be passedalong with a signal stream, such that they are protected by the verysame FEC that is used to protect the information within the signalstream, and such that they may be extracted in a manner for adaptivemodification for use in decoding subsequent FEC blocks.

In the embodiment of this diagram, a single FEC block is shown as beingbetween a CP and the FEC blocks whose FEC decoding parameters arespecified in that CP. However, more than one FEC block may be interposedbetween the CP and these FEC blocks specified by that CP withoutdeparting from the scope and spirit of the invention as well. In fact,within a particular signal stream, the distance between CPs and thecorresponding FEC blocks that are to be decoded using the parametersextracted from those CPs may be variable. For example, the number of FECblocks between a first CP and those FEC blocks specified by that firstCP may be only a singular FEC block. However, the number of FEC blocksbetween a second CP and those FEC blocks specified by that second CP maybe only multiple CPs (e.g., 3 FEC blocks).

FIG. 16 is a diagram illustrating an embodiment of QB (Queue Block) thatmay be implemented in accordance with certain aspects of the invention.This diagram provide in a bit more detail the relationship between theelements of a QB stream and the types of elements that are includedtherein during various stages of processing within the FEC decodingchain functional block. The output from a demodulator, communicativelycoupled to an FEC decoding functional block, is arranged into a streamof TBs (Turbo Blocks) that compose a number of QBs. More specifically,the QB stream may be viewed as including a number of QBs such that eachQB of the QB stream includes a number of TBs. It is also noted that thenumber of TBs within any given QB is variable. However, the manner inwhich each of the TBs within a QB is to be processed (e.g., code rate,modulation type, and/or other parameter) is typically the same. Each ofthe TBs within a given QB is typically processed in a similar manner.

This QB stream (including a plurality of TBs) is provided as the inputto the FEC decoding chain functional block where it undergoes processingwithin each of the various and subsequent functional blocks includedtherein. For example, the individual TBs of the various QBs of the QBstream may initially undergo turbo decoding, de-interleaving, RSdecoding, and subsequently descrambling before being provided to an MPEGpacketizer in some embodiments. The output of the FEC decoding chainfunctional block is a steam of MPEG blocks (i.e., an MPEG stream). ThisMPEG stream may be implemented as an MPEG-2 transport stream in someinstances. It is noted that the alignment of the QBs that are providedto the FEC decoding chain functional block (where the QBs include TBs)is maintained with respect to the output from the FEC decoding chainfunctional block (where the QBs include MPEG blocks). That is to say,the alignment of the various QBs that are input to the FEC decodingchain functional block is maintained after the processing is completed.

FIG. 17A is a diagram illustrating an embodiment of the relationshipbetween latency and overlap queue that may be existent in accordancewith certain aspects of the invention. This diagram shows a situationwhere a single QB is interposed between a CP and the QBs that are to bedecoded according to the parameters contained within that CP. In thisdiagram, a CP1 includes parameters that are used to govern the decodingof QB1, QB2, . . . , QBn, CP2, and QBn+1. It is noted that the CP1includes parameters that are used to govern the manner by which the CP2is to be decoded, and from which parameters are to be extracted togovern decoding of subsequent QBs.

It is also noted that the latency of the FEC decoding chain functionalblock causes the loss of the QBs of the overlap queue. The overlap queuein this embodiment is the QB1 that is immediately after the first CP. Itis also noted that the latency of the FEC decoding chain functionalblock is not strictly a latency associated with the finite amount oftime by which the FEC decoding chain functional block operates at agiven processing rate (e.g., processing speed or clock rate). Thislatency that causes the loss of 1 or more QBs of the overlap queue isnot fixed. Rather, it is a function of the FEC decoding parameterswithin the CP itself. For example, if the manner by which a first groupof QBs (whose decoding is specified by a first CP) is to be decoded isof a much higher order than the manner by which a second group of QBs(whose decoding is specified by a second CP) is to be decoded, then thetime required to decode the first group of QBs will most likely belonger. In that instance, more QBs could potentially be lost given thelonger decoding time required.

For example, looking at one simple example, when decoding with respectto a lower order modulation density (e.g., QPSK), the processingrequires only calculating a few metrics (e.g., 4 in the QPSK case).However, this is much fewer than when decoding with respect to a higherorder modulation density (e.g., 64 QAM), where the processing requirescalculating many more metrics (e.g., 64 in the 64 QAM case). Clearly, itmay take a longer amount of time to calculate 64 metrics as compared toonly 4.

FIG. 17B is a diagram illustrating another embodiment of therelationship between latency and overlap queue that may be existent inaccordance with certain aspects of the invention. This diagram shows asituation where multiple QBs (specifically, 3) are interposed between aCP and the QBs that are to be decoded according to the parameterscontained within that CP. In this diagram, a CP1 includes parametersthat are used to govern the decoding of QB4, . . . , QBn, CP2, andQBn+1. It is noted that the CP1 includes parameters that are used togovern the manner by which the CP2 is to be decoded, and from whichparameters are to be extracted to govern decoding of subsequent QBs. Theoverlap queue in this embodiment includes the QB1, the QB2, and the QB 3that follow after the first CP. It is noted that the number of QBswithin an overlap queue can vary within a given QB stream.

FIG. 18A is a diagram illustrating an embodiment of a receiverarchitecture employing dynamic parameters supported within a framestructure in accordance with certain aspects of the invention. An inputsignal is first provided to a demodulator that performs any of thenecessary demodulation of the received signal to get it into a formatthat is appropriate for subsequent FEC decoding. Then, the output of thedemodulator is provided directly to an FEC decoding chain functionalblock. In contradistinction to the prior art, the output of thedemodulator is not provided also to a parameter extraction functionalblock. The parameter extraction functional block is instead situatedafter the FEC decoding functional block in this novel approach.

Again, the CPs specify the FEC decoding parameters for the packets(e.g., FEC blocks) that are some number of blocks apart from them.Before the CP acquisition is performed by the parameter extractionfunctional block, the FEC decoding chain functional block is configuredfor the CP format (e.g., in some default format as specified by a user)and all packets are decoded as CP. When the FEC decoding functionalblock decodes the non-CP packets, the FEC decoding functional blockgenerates errors because the parameters for the non-CP packets aredifferent than those for the CPs.

Only when the FEC decoding functional block receives an actual CP doesit generate no error. This is how the FEC decoding functional block candetermine that it has in fact received a first CP within the inputsignal stream. After acquiring the first CP, the FEC decoding functionalblock has to skip the packets between the CP and the packets thatactually specified in that CP. For this purpose, the information on theskipped packets must be also embedded in the CP. Once an incoming streamis acquired, the FEC parameters can then change on the fly (i.e., inreal time) based on the parameter information extracted from subsequentCPs. The decoding of the input signal stream is then synchronized as theparameter extraction functional block always then operates to acquirethe FEC decoding parameters from the CPs that pertain to the packetsthat are some number of blocks apart from those respective CPs.

FIG. 18B is a diagram illustrating an embodiment of determination of aCP (Control Packet) MPEG block from among a plurality of MPEG blocks inaccordance with certain aspects of the invention. As mentioned withrespect to the diagram described just above, only when the FEC decodingfunctional block receives an actual CP does it generate no error, andthis is how the FEC decoding functional block can determine that it hasin fact received a first CP within the input signal stream. This diagramshows hardware those TBs that are initially provided to the FEC decodingchain functional block (that are decoded as being expected to be CPs)produce an error (as indicated by the error flag being high. However,when a TB (that is actually a CP) is decoded by the FEC decoding chainfunctional block, then the error flag will be low thereby indicatingthat the TB is in fact a CP.

Several of the following diagrams employ CPs that are shown as being CPMPEG blocks for illustration. However, it is also noted that any othertype of CPs could be employed in alternative embodiments withoutdeparting from the scope and spirit of the invention.

FIG. 19A is a diagram illustrating an embodiment of determination ofindex usage (shown as Q index) within a CP (Control Packet) MPEG blockin accordance with certain aspects of the invention. The use of an indexallows for a condensed representation of the parameters within a CP or aCP MPEG block. In this diagram, a Q index is extracted from an CP MPEGblock and that Q index is passed through a Q parameter mapping table(e.g., a translation table). The size and number of bits of the Q indexis related to the number of parameters that may be specified therein.After the Q index passed through the Q parameter mapping table, thetranslated parameters are then known and the output of the Q parametermapping table is shown as being the CP extracted parameters. These CPextracted parameters may then be employed to adjust the operation of any1 or more of the functional blocks within an FEC decoding chainfunctional block.

FIG. 19B is a diagram illustrating an embodiment of possible format of aCP MPEG block that may be employed in accordance with certain aspects ofthe invention. As mentioned above, the overlap queue is of some concernthen beginning to decode a signal stream. This diagram shows howindividual QB descriptors are included within a CP MPEG block. The sizeof this CP MPEG block is shown as being 188 bytes. Clearly, other sizescould also be employed without departing from the scope and spirit ofthe invention.

The CP MPEG block includes 1 or more headers, and then the various QBdescriptors are included. The first 1 or more QB descriptors are overlapQB descriptor(s) that include all of the parameters (e.g., the FECdecoding parameters) that govern the configuration of the individualfunctional blocks of an FEC decoding chain functional block. The 1 ormore overlap QB descriptor(s) also includes information corresponding tothe total number (#) of QBs that actually in the overlap queue. Asmentioned above, the number of QBs in one overlap queue may differ fromthe number of QBs in another overlap queue. It is also noted that these1 or more overlap QB descriptors are only used when detecting a first CPMPEG block within the MPEG stream. They are discarded from subsequent CPMPEG blocks once the system is in synchronization.

After the 1 or more overlap QB descriptor(s) are 1 or more QBdescriptor(s). These 1 or more QB descriptor(s) are used to direct thedecoding of those QBs that are some distance from the CP MPEG block.That is to say, these 1 or more QB descriptor(s) are used to govern thedecoding of the plurality of QBs for which this particular CP MPEG blockcorresponds. Each of the QB descriptors corresponds to 1 or more QB(s)within the QB stream.

FIG. 19C is a diagram illustrating another embodiment of possible formatof a CP MPEG block that may be employed in accordance with certainaspects of the invention. This diagram shows an alternative format of aCP MPEG block. In this embodiment, the CP MPEG block includes no overlapQB descriptors at all. A FEC decoding chain functional block simplyskips a predetermined number of QBs before decoding the QBs using the CPextracted parameters. This is a simplified embodiment where a defaultapproach is used to govern the decoding of the FEC decoding chainfunctional block simply operates according to a predetermined approach(i.e., by skipping a predetermined number of QBs or decoding thosepredetermined number of QBs according to a predetermined approach beforeusing the CP extracted parameters for decoding of subsequent QBs).

Several of the following diagrams provide possible alternative andembodiments of form that a QB descriptor may have. These QB descriptorsmay be implemented within either of the two possible embodiments of CPMPEG blocks described above.

FIG. 20 is a diagram illustrating an embodiment of general format of aQB (Queue Block) descriptor (employing 2 bytes) in accordance withcertain aspects of the invention. The QB descriptor is partitioned intoa plurality of bit fields such that the number of bits within each bitfield may be selected by a designer. A repeat field is shown asincluding a bits (where a is an integer as selected by a designer). Anoverlap field is shown as including only 1 bit. This 1 bit of theoverlap field indicates whether the QB descriptor is an overlapdescriptor or a non-overlap descriptor. An opcode field is shown asincluding c bits (where c is an integer as selected by a designer). Thefinal bit field in this embodiment is a Q index field that is shown asincluding d bits (where d is an integer as selected by a designer).

The repeat field operates to specify the number of QBs to be repeatedand decoded using the parameters extracted from this particular QBdescriptor. Generally speaking, the repeat field can be employed tospecify up to 2^(a) QBs that are to be repeated. The overlap fieldspecifies whether the QB descriptor is an overlap descriptor or anon-overlap descriptor. The opcode field operates to specify the QBdescriptor type that is included within this particular QB descriptor.The Q index field includes the information that is translated using theQ parameter mapping table to determine the particular parameters so thatan FEC decoding chain functional block may be appropriately configuredto decode the QBs for which this QB descriptor corresponds. It is alsonoted that additional Q indices may also be employed in alternativeembodiments (e.g., within a sequence repeat descriptor, one embodimentof which is described below).

The following 2 diagrams show more specific possible embodiments of howQB descriptors may be implemented in accordance with the invention.

FIG. 21 is a diagram illustrating an embodiment of a format of a QBrepeat descriptor (employing 2 bytes), and having 1 Q index, inaccordance with certain aspects of the invention. In this embodiment, a4 bit repeat field is employed to specify the number of QBs to berepeated and decoded using the parameters extracted from this particularQB descriptor. In this embodiment, up to 2⁴=16 QBs may be specified tobe repeated and decoded. A single bit overlap field specifies whetherthe QB descriptor is an overlap descriptor or a non-overlap descriptor.Specifically, when the single bit of the overlap field is 1, then anoverlap queue actually exists. However, when the single bit of theopcode field is 0, then the operation is according to normal operationwithout dealing with an overlap queue.

A 3 bit opcode field specifies the QB descriptor type. In thisembodiment, when the bit values of the opcode field are 001, then itindicates that only 1 Q index is included within this particular QBdescriptor. In addition, a 4 bit Q index is used with a Q parametermapping table for CP parameter extraction from this particular QBdescriptor.

FIG. 22 is a diagram illustrating an embodiment of a format of a QBsequence repeat descriptor (employing multiple bytes), and havingmultiple Q indices, in accordance with certain aspects of the invention.This embodiment is somewhat similar to the embodiment described justabove. For example, in this embodiment, a 4 bit repeat field is againemployed to specify the number of QBs to be repeated and decoded usingthe parameters extracted from this particular QB descriptor. In thisembodiment, up to 2⁴=16 QBs may be specified to be repeated and decoded.Again, a single bit overlap field specifies whether the QB descriptor isan overlap descriptor or a non-overlap descriptor. Specifically, whenthe single bit of the overlap field is 1, then an overlap queue actuallyexists. However, when the single bit of the overlap field is 0, then theoperation is according to normal operation without dealing with anoverlap queue.

Again, a 3 bit opcode field specifies the QB descriptor type. However,in this embodiment, when the bit values of the opcode field are 010,then it indicates that multiple Q indices are included within this QBdescriptor. This also indicates that an additional field is includedwithin the QB descriptor that indicates how many times to repeat thesequence of Q indices to the QBs of the QB stream to which thisparticular QB descriptor applies. For example, a value of 0010(binary)=2 in this field would indicate that the sequence of Q indicesshown immediately below is to be repeated twice, and a value of 0100(binary)=4 in this field would indicate that the sequence of Q indicesshown immediately below is to be repeated four times. The actualsequence of Q indices is situated below the field indicating the numberof times the sequence of Q indices is to be repeated.

FIG. 23 is a diagram illustrating an embodiment of CP (Control Packet)processor functionality that may be implemented in accordance withcertain aspects of the invention. This diagram shows in perhaps moreclear representation that the operation of a CP processor. An MPEGstream is input to the CP processor, and the extraction of the 1 or moreQ indices is performed from the QB descriptor of a CP MPEG block. It isnoted that if the current CP MPEG block being processed is the first CPMPEG block encountered within the MPEG stream, then the processing mayinvolve the extraction of Q indices from an overlap descriptor, but thisis performed only in this instance when the current CP MPEG block beingprocessed is the first CP MPEG block encountered within the MPEG stream.Otherwise, the type of QB descriptors from which the Q indices may beextracted may be of the non-overlap descriptor types.

Once the Q indices have been extracted, then the Q indices are providedinto a Q index FIFO (First-In First-Out) buffer. Thereafter, each of thecorresponding Q indices are processed through a Q parameter mappingtable (e.g., a translation table) where the actual values for thecorresponding parameters are determined for use in appropriateconfiguration of 1 or more of the functional blocks within an FECdecoding chain functional block. After processing a given Q indexthrough the Q parameter mapping table, the now determined and extractedFEC parameters may be use to configure 1 or more of the functionalblocks within an FEC decoding chain functional block.

The operation of the CP processor may be viewed as performing andsupporting the functionality of parameter extraction from a CP MPEGblock. The operation of the CP processor may also be initiated upon thedetection of a CP MPEG block from among a plurality of MPEG blockswithin an MPEG stream. That is to say, the CP processor need not beoperating in an attempt to extract parameters from each and every MPEGblock of an MPEG stream. Rather, the CP processor can be directed tooperate to extract the parameters from the current MPEG block only whenthe current MPEG block has been determined to be a CP MPEG block.

FIG. 24 is a flowchart illustrating an embodiment of a method for FEC(Forward Error Correction) decoding of a frame structure supportingdynamic FEC parameters that may be performed in accordance with certainaspects of the invention.

The method involves decoding of MPEG blocks (i.e., of an MPEG stream)prior to performing CP (Control Packet) parameter acquisition from afirst CP MPEG block within the MPEG stream. In doing this decodingapproach, prior to performing CP parameter acquisition, the FEC decodingchain is configured for a predetermined CP format and all of the MPEGblocks to be decoded as CP MPEG blocks. Accordingly, the FEC decodingthat is performed on non-CP MPEG blocks generates errors (which may beused to indicate a non-CP MPEG block), and the FEC decoding that isperformed on CP MPEG blocks generates no error (which may be used toindicate a CP MPEG block).

Once an MPEG block undergoes FEC decoding using the FEC decoding chainfunctional block as having no error, the method involves detecting a CPMPEG block within the input signal stream (e.g., from among a pluralityof MPEG blocks). Once this CP MPEG block has been appropriatelyidentified, then the method involves performing CP parameter acquisitionfrom the detected CP MPEG block.

It is also noted that the method involves FEC decoding of the MPEGblocks immediately after CP; the FEC decoding of the MPEG blocks in theoverlap queue is performed using the CP queue type. Because of this,MPEG errors generated there from. The overlap descriptors and extractedparameters operate to provide for synchronization within the decodingprocessing. This provides information corresponding to how many turbocode blocks the CP queue has, and information corresponding to how manyturbo blocks the whole overlap part has may be extracted. By havingthese two pieces of information, it may be determined where to begindecoding using the actual FEC parameters extracted from non-overlapdescriptors. This determination of where to begin decoding using theactually extracted FEC parameters may be viewed as a “boot-strapping”situation that must only be dealt with once until the system issynchronized.

Once these FEC decoding parameters have been extracted from the CPpacket, the method involves feeding back the acquired CP parameters to 1or more of the functional blocks within the FEC decoding chainfunctional block to assist in decoding of the subsequent MPEG blocksthereby synchronizing the FEC decoding and the parameter acquisition ofthe MPEG stream. The method then continues by performing steady-statesynchronized FEC decoding of subsequent MPEG blocks and by performingparameter acquisition of subsequent CP MPEG blocks of the input signalstream. In steady-state operation, although there is some degree oflatency in the FEC decoding, none of the queues are wasted insteady-state operation because the FEC decoding parameters for theoverlap queues are specified in the previous CP.

FIG. 25 is a flowchart illustrating an embodiment of a method for CP(Control Packet) processing that may be performed in accordance withcertain aspects of the invention. The method initially involvesreceiving a plurality of MPEG blocks. These MPEG blocks may be viewed asbeing an MPEG stream in some situations. The method then involvesdetermining that an MPEG block (of the plurality of MPEG blocks) is infact a CP MPEG block. The method then operates by extracting 1 or moreQB descriptors from the determined CP MPEG block. When processing afirst CP MPEG block of the MPEG blocks, the method may be performed toinvolve extracting an overlap descriptor there from. The method may alsoalternatively involve extracting a repeat descriptor from the CP MPEGblock or extracting a sequence repeat descriptor from the CP MPEG block.

When processing the descriptors (i.e., the QB descriptors) from the CPMPEG block, the method involves extracting 1 or more Q indices from theQB descriptors. Once the 1 or more Q indices have been extracted, themethod involves determining 1 or more parameters by processing theextracted 1 or more Q indices using a Q parameter mapping table.Afterwards, the method involves providing the determined 1 or moreparameters to 1 or more functional blocks within an FEC decoding chain.

FIG. 26 is a flowchart illustrating an embodiment of a method foradaptively changing frame structure and frame content based on operatingconditions in accordance with certain aspects of the invention. Themethod involves transmitting a first signal downstream according to afirst frame structure and a first frame content. Then, the methodinvolves receiving the first signal, and determining 1 or more indiciacorresponding to the operating conditions there from. An example pieceof information that is indicative of the operating conditions is SNR(Signal to Noise Ratio). However, other indicia of operating conditionscould also be employed without departing from the scope and spirit ofthe invention.

The method then involves providing the 1 or more indicia correspondingto the operating conditions upstream (for use in subsequenttransmitting). The method then involves transmitting a second signaldownstream according to a second frame structure and a second framecontent. This second frame structure and a second frame content may beselected based on the 1 or more indicia corresponding to operatingconditions of a communication system. This method provides a means bywhich adaptive modification of the frame structure and frame contentemployed within a communication system may be modified. The variousapproaches provided herein provide a means by which parameters thatgovern FEC decoding may be very effectively and efficiently modified inresponse to any changes in operating condition.

A very simplistic example is provided below by which this method may beperformed. Three different possible queue types are considered in thisvery simplistic example.

Queue type A: ½ QPSK

Queue type B: ⅔ 8 PSK

Queue type C: 16 QAM

1 or more subscriber modem(s) can report indicia corresponding to theoperating conditions (e.g., their SNR) to the headend using an upstreamchannel. When all of the subscriber modem(s) are in a poor operatingcondition (e.g., poor SNR condition), the headend sends downstreamsignal only using queue type A. When the operating condition (e.g., SNR)in some subscribers improves, it starts using queue type B. When the SNRcondition improves more, it starts using queue type C. Also, it canchange the number of QBs with each queue type adaptively. Generallyspeaking, the headend chooses the appropriate queue types from among apre-determined set of queue types and then builds downstream framesbased on the subscriber's operating condition (e.g., SNR).

It is also noted that the methods described within the preceding figuresmay also be performed within any of the appropriate system and/orapparatus designs (communication systems, communication transmitters,communication receivers, communication transceivers, and/orfunctionality described therein) that are described above withoutdeparting from the scope and spirit of the invention.

Moreover, it is noted that the receiver architecture, methods, and otherfunctionality presented herein can operate at a much lower SNR, whencompared to prior art approaches, thanks to the FEC correctioncapability for the CPs provided herein. The ability to protect the CPsusing FEC allows for a much improved performance when compared to theprior art.

In view of the above detailed description of the invention andassociated drawings, other modifications and variations will now becomeapparent. It should also be apparent that such other modifications andvariations may be effected without departing from the spirit and scopeof the invention.

1. A receiver, comprising: a demodulator that is operable to demodulatean input signal stream thereby generating a demodulated signal streamthat includes FEC (Forward Error Correction) blocks; an FEC decodingchain functional block that is operable to be configured to perform FECdecoding of a first plurality of FEC blocks of the demodulated signalstream using a first plurality of FEC decoding parameters; wherein theFEC decoding chain functional block is operable to detect a CP (ControlPacket) when performing FEC decoding of the first plurality of FECblocks of the demodulated signal stream; a parameter extractionfunctional block that is operable to extract a second plurality of FECdecoding parameters from the CP; wherein the parameter extractionfunctional block is operable to provide the second plurality of FECdecoding parameters to the FEC decoding chain functional block; whereinthe FEC decoding chain functional block is operable to be reconfiguredto perform subsequent FEC decoding using the second plurality of FECdecoding parameters; wherein the second plurality of FEC decodingparameters corresponds to a second plurality of FEC blocks that islocated a number of FEC blocks after the CP within the demodulatedsignal stream; and wherein the FEC decoding chain functional blockperforms FEC decoding of the second plurality of FEC blocks of thedemodulated signal stream using the second plurality of FEC decodingparameters.
 2. The receiver of claim 1, wherein: the FEC blocks of thedemodulated signal stream are QBs (Queue Blocks) such that each QBincludes a corresponding plurality of TBs (Turbo Blocks); the FECdecoding chain functional block performs FEC decoding on the QBs therebygenerating MPEG (Moving Picture Experts Group) blocks; and the CP is aCP MPEG block.
 3. The receiver of claim 1, wherein: the FEC decodingchain functional block includes a plurality of functional blocks suchthat operation of each functional block therein is governed by at leastone parameter; the CP includes at least one QB (Queue Block) descriptorthat contains a condensed representation of a plurality of parameters;the parameter extraction functional block processes the QB descriptor toextract the second plurality of FEC decoding parameters from the CP; andthe parameter extraction functional block provides the extracted secondplurality of FEC decoding parameters back to the FEC decoding chainfunctional block to adjust at least one parameter of the plurality ofparameters thereby modifying the operation of at least one functionalblock of the plurality of functional blocks within the FEC decodingchain functional block when decoding the second plurality of FEC blocks.4. The receiver of claim 1, wherein: the FEC decoding chain functionalblock includes a plurality of functional blocks such that operation ofeach functional block therein is governed by at least one parameter; theCP includes at least one QB (Queue Block) descriptor that contains acondensed representation of a plurality of parameters; and the QBdescriptor is a QB repeat descriptor or a QB sequence repeat descriptor.5. The receiver of claim 1, wherein: the FEC blocks of the input signalstream are MPEG (Moving Picture Experts Group) blocks; the CP is a CPMPEG block; the FEC decoding chain functional block includes a pluralityof functional blocks such that operation of each functional blocktherein is governed by at least one parameter; a first functional blockwithin the FEC decoding chain functional block is a turbo decoder; theat least one parameter that governs operation of the turbo decoder is atleast one of a turbo code rate, a number of TBs (Turbo Blocks) withinthe FEC blocks of the demodulated signal stream, and a constellationscaling parameter; a second functional block within the FEC decodingchain functional block is a de-interleaver that is communicativelycoupled to the turbo decoder; the at least one parameter that governsoperation of the de-interleaver is at least one of an interleaver depthand an interleaver block length; a third functional block within the FECdecoding chain functional block is a RS (Reed Solomon) decoder that iscommunicatively coupled to the de-interleaver; the at least oneparameter that governs operation of the RS decoder is at least one of anumber of errors the RS decoder can accommodate (T_(c)), an RS blocklength, and a number of RS blocks; a fourth functional block within theFEC decoding chain functional block is a descrambler that iscommunicatively coupled to the RS decoder; and the at least oneparameter that governs operation of the descrambler is a number of MPEGblocks to be descrambled.
 6. The receiver of claim 1, wherein: FECblocks that have been processed by the FEC decoding chain functionalblock are provided to a MAC (Medium Access Controller).
 7. The receiverof claim 1, wherein: the FEC decoding chain functional block is operableto generate an error flag when decoding the CP; and the error flag isoperable to direct the parameter extraction functional block to processthe CP to extract the second plurality of FEC decoding parameters fromthe CP.
 8. The receiver of claim 1, wherein: the CP includes at leastone overlap QB (Queue Block) descriptor; and when the CP is a firstdetected CP within the demodulated signal stream, the parameterextraction functional block processes the overlap QB descriptor toextract synchronization information there from.
 9. The receiver of claim8, wherein: when the CP is a CP that is detected after the firstdetected CP within the demodulated signal stream, the overlap QBdescriptor is discarded.
 10. The receiver of claim 1, wherein: thereceiver is implemented within a communication device; and thecommunication device is implemented within at least one of a one-waysatellite communication system, a two-way satellite communicationsystem, and an HDTV (High Definition Television) communication system.11. A receiver, comprising: a demodulator that is operable to demodulatean input signal stream thereby generating a QB (Queue Block) stream suchthat each QB within the QB stream includes a corresponding plurality ofTBs (Turbo Blocks); an FEC (Forward Error Correction) decoding chainfunctional block that is operable to be configured to perform FECdecoding of a first portion of the QB stream that includes a firstplurality of QBs using a first plurality of FEC decoding parametersthereby generating a first portion of an MPEG stream that includes afirst plurality of MPEG blocks; wherein the FEC decoding chainfunctional block is operable to detect a CP (Control Packet) MPEG blockwhen performing FEC decoding of the first plurality of QBs; a CPprocessor that is operable to perform parameter extraction of a secondplurality of FEC decoding parameters from the CP MPEG block; wherein theCP processor is operable to provide the second plurality of FEC decodingparameters to the FEC decoding chain functional block; wherein the FECdecoding chain functional block is operable to be reconfigured toperform subsequent FEC decoding using the second plurality of FECdecoding parameters such that the second plurality of FEC decodingparameters corresponds to a second portion of the QB stream that islocated a number of QB blocks after the QB from which the CP MPEG blockis generated; and wherein the FEC decoding chain functional block isoperable to perform FEC decoding of the second portion of the QB streamthat includes a second plurality of QBs using the second plurality ofFEC decoding parameters thereby generating a second portion of the MPEGstream that includes a second plurality of MPEG blocks.
 12. The receiverof claim 11, wherein: a first QB of the QB stream includes a firstplurality of TBs; and a second QB of the QB stream includes a secondplurality of TBs.
 13. The receiver of claim 11, wherein: the FECdecoding chain functional block includes a plurality of functionalblocks such that operation of each functional block therein is governedby at least one parameter; the CP MPEG block includes at least one QBdescriptor that contains a condensed representation of a plurality ofparameters; the CP processor is operable to perform parameter extractionby processing the QB descriptor to extract the second plurality of FECdecoding parameters from the CP MPEG block; and the CP processorprovides the extracted second plurality of FEC decoding parameters backto the FEC decoding chain functional block to adjust at least oneparameter of the plurality of parameter thereby modifying the operationof at least one functional block of the plurality of functional blockswithin the FEC decoding chain functional block when decoding the secondportion of the QB stream that includes the second plurality of QBs. 14.The receiver of claim 11, wherein: the FEC decoding chain functionalblock includes a plurality of functional blocks such that operation ofeach functional block therein is governed by at least one parameter; theCP includes at least one QB (Queue Block) descriptor that contains acondensed representation of a plurality of parameters; and the QBdescriptor is a QB repeat descriptor or a QB sequence repeat descriptor.15. The receiver of claim 11, wherein: the FEC decoding chain functionalblock includes a turbo decoder whose operation is governed by at leastone turbo decoder parameter; the turbo decoder is coupled to ade-interleaver whose operation is governed by at least onede-interleaver parameter; the de-interleaver is coupled to a RS (ReedSolomon) decoder whose operation is governed by at least one RS decoderparameter; the RS decoder is coupled to a descrambler whose operation isgoverned by at least one descrambler parameter; and the descrambler iscoupled to an MPEG packetizer.
 16. The receiver of claim 15, wherein:the at least one turbo decoder parameter is at least one of a turbo coderate, a number of TBs within a QB, and a constellation scalingparameter; the at least one de-interleaver parameter is at least one ofan interleaver depth and an interleaver block length; the at least oneRS decoder parameter is at least one of a number of errors the RSdecoder can accommodate (T_(c)), an RS block length, and a number of RSblocks; and the at least one descrambler parameter is a number of MPEGblocks to be descrambled.
 17. The receiver of claim 11, wherein: MPEGblock that have been processed by the FEC decoding chain functionalblock are provided to a MAC (Medium Access Controller).
 18. The receiverof claim 11, wherein: the FEC decoding chain functional block isoperable to generate an error flag when decoding the CP MPEG block; andthe error flag is operable to direct the CP processor to process the CPMPEG block to extract the second plurality of FEC decoding parametersfrom the CP MPEG block.
 19. The receiver of claim 11, wherein: the CPMPEG block includes at least one overlap QB (Queue Block) descriptor;and when the CP MPEG block is a first detected CP MPEG block within thedemodulated signal stream, the parameter extraction functional blockprocesses the overlap QB descriptor to extract synchronizationinformation there from.
 20. The receiver of claim 19, wherein: when theCP MPEG block is a CP MPEG block that is detected after the firstdetected CP MPEG block within the demodulated signal stream, the overlapQB descriptor is discarded.
 21. The receiver of claim 11, wherein: thereceiver is implemented within a communication device; and thecommunication device is implemented within at least one of a one-waysatellite communication system, a two-way satellite communicationsystem, and an HDTV (High Definition Television) communication system.22. A method for FEC (Forward Error Correction) decoding of a framestructure supporting dynamic FEC parameters, the method comprising:decoding a first plurality of FEC blocks of a demodulated signal streamaccording to an FEC decoding chain; detecting a first CP (ControlPacket) from among the first plurality of FEC blocks of the demodulatedsignal stream when decoding the first plurality of FEC blocks;performing parameter acquisition to extract at least one parameter fromthe first detected CP; modifying operation of at least one decodingprocess within the FEC decoding chain in accordance with the extractedat least one parameter; and performing steady-state synchronized FECdecoding of a second plurality of FEC blocks and parameter acquisitionfrom a second detected CP among the second plurality of FEC blocks. 23.The method of claim 22, wherein: the FEC blocks of the demodulatedsignal stream are QBs (Queue Blocks) such that each QB includes acorresponding plurality of TBs (Turbo Blocks); the decoding according tothe FEC decoding chain on the QBs operates to generate MPEG (MovingPicture Experts Group) blocks; and the CP is a CP MPEG block.
 24. Themethod of claim 22, wherein: the FEC decoding chain performs a pluralityof processes such that operation of each process therein is governed byat least one parameter; the CP includes at least one QB (Queue Block)descriptor that contains a condensed representation of a plurality ofparameters; parameter acquisition is performed to process the QBdescriptor to extract the second plurality of FEC decoding parametersfrom the CP; and the second plurality of FEC decoding parameters areprovided to the FEC decoding chain to adjust at least one parameter ofthe plurality of parameters thereby modifying the operation of at leastprocess of the plurality of processes within the FEC decoding chain whendecoding the second plurality of FEC blocks.
 25. The method of claim 22,wherein: the FEC decoding chain performs a plurality of processes suchthat operation of each process therein is governed by at least oneparameter; the CP includes at least one QB (Queue Block) descriptor thatcontains a condensed representation of a plurality of parameters; andthe QB descriptor is a QB repeat descriptor or a QB sequence repeatdescriptor.
 26. The method of claim 22, further comprising: providingFEC blocks that have been processed by the FEC decoding chain to a MAC(Medium Access Controller).
 27. The method of claim 22, wherein: the FECdecoding chain is operable to generate an error flag when decoding theCP; and the error flag is operable to direct parameter extraction toprocess the CP to extract the second plurality of FEC decodingparameters from the CP.
 28. The method of claim 22, wherein: a CPincludes at least one overlap QB (Queue Block) descriptor; and furthercomprising: when the CP is the first detected CP within the demodulatedsignal stream, processing the overlap QB descriptor to extractsynchronization information there from.
 29. The method of claim 28,further comprising: when the CP is a CP that is detected after the firstdetected CP within the demodulated signal stream, discarding the overlapQB descriptor.
 30. The method of claim 22, wherein: the method isperformed within a communication device; and the communication device isimplemented within at least one of a one-way satellite communicationsystem, a two-way satellite communication system, and an HDTV (HighDefinition Television) communication system.